"Because of the potential for NCAA violations, the university notified the NCAA today, and the four football players will be held out of practice and competition until the conclusion of an ongoing investigation and the University honor code process. Any possible academic dishonesty by other students will be addressed appropriately," the school said in a statement Friday afternoon.

The university said there was evidence that students had submitted papers and homework that had been written for them by others. That was initially detected at the end of the summer session and referred to the athletic compliance office on July 29. An immediate investigation was launched by the office of general counsel and is ongoing.

The school said if there is a determination the students would have been ineligible during previous competition, the Fighting Irish would "voluntarily vacate any victories in which they participated."

The scandal reportedly stretched beyond the football program. According to Yahoo! Sports, the investigation included non-athletes as well.

Athletic director Jack Swarbrick and president Rev. John I. Jenkins addressed the matter at a press conference later on Friday.

"Integrity is at the heart of our mission and academic misconduct will not be tolerated at Notre Dame," Jenkins said in a statement. "If the suspected improprieties are proven, we will use the experience to reinforce among our students the importance of honesty in all that they do. We are also examining ways of better conveying to students that they can avail themselves of legitimate academic assistance without resorting to cheating."

Jenkins said there is no evidence head football coach Brian Kelly or his coaches, along with the academic staff, knew about the issue. Jenkins also said Notre Dame contacted the NCAA Friday morning and the organization is "comfortable" with the steps the school is taking at the present time.

Daniels is Notre Dame's leading returning receiver, having racked up 745 yards and seven touchdowns last season. Russell has started all 26 games in his Irish career, while Williams has appeared in 35 games over three seasons.

The university said students who are subject to the investigation will remain enrolled until its conclusion.